C-type lectin-like venom protein (Snaclec)

C-type lectin-like venom proteins, or Snaclecs, are a major family of non-enzymatic toxins prevalent in the venoms of African vipers, including the West African carpet viper (Echis ocellatus) and the puff adder (Bitis arietans) (Clemetson, 2010). These proteins are structurally related to C-type lectins but have lost their carbohydrate-binding ability, instead evolving to target critical components of the mammalian hemostatic system, such as platelet receptors (e.g., GPIb, GPVI, CLEC-2) and coagulation factors (e.g., Factors IX and X) (Calvete et al., 2007). By binding to these targets, Snaclecs can cause either profound platelet activation leading to microvascular thrombosis or inhibition of platelet function and coagulation, contributing to the severe systemic hemorrhage characteristic of viper envenomation (Wagstaff et al., 2009). In clinical practice, these proteins are the primary targets for antivenom therapies, such as EchiTAb-Plus-ICP and SAIMR Polyvalent, which contain antibodies designed to neutralize toxin activity (Casewell et al., 2014). Research into Snaclecs is vital for improving the efficacy of antivenoms and for the potential development of new anticoagulants or antiplatelet drugs derived from their unique binding properties. Their diversity across species necessitates the use of polyvalent antivenoms to ensure broad coverage against different Snaclec variants found in various African viperid venoms. Furthermore, the rapid onset of action of these toxins makes early administration of antivenom critical for patient survival.

Other names

Snake venom C-type lectinSnaclecC-type lectin-like proteinCTLPCLPSnake venom C-type lectin-related protein

Neutralization of toxin activity through antibody binding, preventing interaction with host physiological targets such as platelets and coagulation factors (Casewell et al., 2014).